Perhaps they dropped it because Scala is driven more by academics who didn't take that into account (or did and dismissed it).
We did consider (and regret) potentially leaving android behind, but we were (perhaps naively) hoping that something like retrolambda would suffice, or that android would catch up. In any case, it doesn't make a lot of sense to have 2.12 still support Java 6, since most of its features require Java 8 (those that don't, we first implemented in 2.11.x).
As announced in http://scala-lang.org/news/2.12-roadmap/, we will continue to support 2.11 for a bit longer than most releases, and we welcome community backports of 2.12 features that you'd like to see in 2.11.
Presumably 2.11 won't be supported going forward? Or as someone who would like my libraries to work on android and doesn't particularly care about them being callable from Java 8, should I just stay on 2.11 indefinitely?
a) Java 6 is forward binary compatible with later versions
b) Google has a reasonable excuse in terms of the Oracle lawsuit. Don't get me wrong, I'm not happy about Android being stuck on Java 6, but there are extenuating circumstances.
c) Scala 2.11 has issues that affect me and I want to see fixed. Java 6 doesn't, at least not that I've noticed. (If JVM 8 were necessary to the implementation of a Scala feature I cared about I would understand that, but as far as I can see it's irrelevant to my use cases)
I would guess there's probably quite a few VB6 applications out there in business-land, and it's been EOL'd since 2012 IIRC. Not that most people would want to deal with them, but they exist, just like Java 6 in Android.